“This hypothesis fits well with previous observational findings on the protective role of fibre and low-fat high-complex carbohydrate diet for T2D,”​ the study put forward.

“The role of microbiota in e.g. efficient conversion of complex indigestible dietary carbohydrates into short-chain fatty acids and maintenance of gut microbiome carbohydrate fermentation seem to be important to maintain gut and systemic health.”​

METSIM and VIP​

The findings from this study closely mimic those in two comparable studies, which also highlighted the protective role of indolepropionic acid.

In the METSIM (Metabolic Syndrome in Men) study, Finnish researchers also found during a 5-year follow-up that indolepropionic acid was lower in subjects who developed T2D than in those who remained non-diabetic.

The Swedish Västerbotten Intervention Program (VIP) found that indolepropionic acid was around 15% lower in T2D cases than in their matched healthy controls at baseline and was negatively associated with T2D incidence.

Despite the strength of all three findings, the researchers highlighted a few limitations that may have had a bearing on the results.

These include the use of samples collected one year after the onset of the study as baseline samples available at the start of the trial were not available.

Additionally, insulin secretion and insulin sensitivity were not measured either by the hyperinsulinaemic-euglycaemic clamp or the intravenous glucose tolerance test (IVGTT), a method considered the ‘gold standard’ of measuring insulin resistance.